Penetration Test:

A viscosity is measured indirectly by the penetration of a standard needle under standard conditions of load, time and temperature. The test measures the hardness or softness of bitumen in terms of penetration expressed in units of mm/10 of the standard needle. The standard conditions are:

Temperature :           25^oC

Load               :           100 gm

Time over which penetration is recorded : 5 secs

A diagram of the set-up is given in Figure.

Figure: Penetration Test for Paving Bitumen

Bituminous of the following penetration grade are available in India:

Penetration    30/40

Penetration    60/70

Penetration    80/100